The present invention relates in general to laser enclosures and, more particularly, to such an enclosure having at least one workpiece positioner for alternately moving workpieces from a workpiece loading/unloading zone, through an opening in the enclosure housing to a work zone within the housing and for sealingly mating with the housing to prevent laser energy from exiting the housing during a laser operation.
Industrial lasers are known in the prior art. Such lasers are commonly used for purposes of welding and cutting. U.S. and international standards have been developed which divide all industrial lasers into four major hazard categories, i.e., four broad classes (I to IV). The weakest lasers are Class I lasers which emit laser radiation below known hazard levels. The strongest lasers are Class IV lasers which are hazardous to view under any condition (directly or diffusely scattered) and are a potential fire hazard and a skin hazard.
Laser enclosures are also known in the prior art. Such enclosures are commonly used as protective enclosures for higher powered lasers, e.g., Class II, Class III or Class IV lasers, and allow the higher powered lasers to operate in a lower classification. For example, some Class I industrial lasers consist of a higher class laser enclosed in a properly interlocked and labeled protective enclosure.
One laser enclosure found in the prior art encases a laser workstation. Associated with the workstation is a laser device which acts to generate and direct a laser beam to the workstation for performing laser operations upon workpieces that pass into the enclosure.
The noted laser enclosure comprises three stationary walls, a stationary ceiling and a fourth stationary wall having an opening through which workpieces pass into and out of the inner cavity of the enclosure. The enclosure includes a rotary turntable having four vertical partitions that attach to a hub at the turntable's center of rotation, which is coplanar with the fourth stationary wall. Positioned between the four vertical partitions are four fixtures for mounting workpieces onto the rotary turntable.
Portions of two of the vertical partitions are sealed to a portion of the fourth stationary wall by hinged flaps to inhibit the escape of laser radiation from the enclosure. Those flaps are moved between sealing and non-sealing positions by a plurality of pneumatic cylinders. Operation of the cylinders is time consuming, resulting in an undesirable pause occurring between laser operations. Accordingly, this active sealing arrangement is a substantial limitation on welding efficiency, especially where a series of successive workpieces is to be welded. Furthermore, since this sealing arrangement requires movable sealing flaps, i.e., non-static sealing members to effect sealing, it is complex and costly to produce.
U.S. Pat. No. 4,205,216 to Douglas discloses a laser enclosure comprising a plurality of stationary walls, a stationary ceiling and a front stationary wall having an opening through which workpieces pass into and out of the inner cavity of the enclosure. The enclosure includes a rotary turntable having a plurality of vertical baffles that extend to a hub at the turntable's center of rotation. Positioned between the vertical baffles are fixtures for mounting workpieces onto the rotary turntable. This enclosure is provided with only a single workpiece transport device, namely, the rotary turntable. The overall processing time required for welding a given number of workpieces with this apparatus can be decreased by, for example, decreasing the time required to index the single rotary turntable one position. This, however, is oftentimes problematic to accomplish when larger workpieces are involved due to the size and weight of the workpieces as well as the size and weight of the turntable required to support such workpieces.
Accordingly, there is a need for an improved laser enclosure which achieves sealing without requiring active drive devices or complex movable sealing members. There is further a need for an improved laser enclosure which can quickly and efficiently move large workpieces into and out of the interior of the enclosure housing, thereby reducing the overall processing time for a given number of such workpieces.